'Linux programming' is fairly vague, but whatever you end up doing (C#/Mono, C/kernel, erlang, LISP, etc it's all there), you definitely want to learn (bash) sh

'Linux programming' is fairly vague, but whatever you end up doing (C#/Mono, C/kernel, erlang, LISP, etc it's all there), you definitely want to learn (bash) shell programming and either Perl or Python because that's what most distros use for automation. You can't really get a firm grip on any distro without learning that part.